Low-level permutations

class sage.combinat.permutation_nk.PermutationsNK(n, k)

Bases: sage.combinat.combinat.CombinatorialClass

cardinality()

Returns the number of permutations of k things from a list of n things.

EXAMPLES:

sage: from sage.combinat.permutation_nk import PermutationsNK
sage: PermutationsNK(3,2).cardinality()
6
sage: PermutationsNK(5,4).cardinality()
120

random_element()

Returns a random permutation of k things from range(n).

EXAMPLES:

sage: from sage.combinat.permutation_nk import PermutationsNK
sage: PermutationsNK(3,2).random_element()
[0, 1]